text="To be not to be,that is the question"
letters_set=set()
letter_count={}
for char in text:
    if char.isalpha():
        letters_set.add(char.lower())
        if char.lower() in letter_count:
            letter_count[char.lower()] +=1
        else:
            letter_count[char.lower()]=1
for letter in letters_set:
    count=letter_count[letter]
    print(f"{letter}:{count}")